CHINA'S repeated warnings to North Korea to abandon its nuclear program have reportedly been ignored, as efforts to mend strained ties between the two nations appear to fizzle out.

North Korean leader Kim Jong Un will not listen to China's requests a source has suggested

After North Korea sent a high-level confidant to Beijing last month, China reportedly insisted that Pyongyang should stop conducting nuclear and missile tests.

However, it is doubtful the North will heed the request, a source has now sensationally revealed.

After months of near-daily vows from Pyongyang to obliterate Washington and Seoul with nuclear force, Kim dispatched Choe Ryong-hae, vice chairman of the country's top military body, to explain North Korea's recent actions to China.

But he got a lukewarm reception from his Chinese hosts, the source, who has close ties to Beijing and Pyongyang, revealed.

"There was no bear hug between Wang Jiarui and Choe when they met," the source noted, referring to the Chinese Communist Party's International Department minister.

Such greetings have been a tradition between North Korean and Chinese leaders, who once saw their relationship as "close as lips and teeth".

Experts said Choe's three-day visit was a desperate attempt by North Korea to mend fences with its only major diplomatic ally.

North Korea's increased hostility in April and May drew international condemnation and put Beijing under pressure, especially from Washington, to rein in Pyongyang.

But after Beijing tried to convince Pyongyang to stop its nuclear and missile tests during the talks, tensions do not appear to have lessened, said the source.

"(North) Korea has not mellowed," said the source, who did not attend the meetings but has since spoken to both sides to which he has regular access.

After the meetings, in which Choe eventually held talks with Chinese President Xi Jinping, North Korea promised to take "positive steps for peace" while China repeated its mantra of wanting "calm and restraint" on the Korean peninsula.

However, North Korea has repeatedly said it will never abandon its nuclear weapons, calling them its "treasured sword".

The source did not say if Beijing spelt out any consequences should the North conduct further tests.

The head of the Chinese leadership's international affairs office, meets with North Korea's rep

Top Chinese officials now emphasize that the principal goal is to terminate the nuclear weapons programme

U.S. official

During the tense meetings last month, Choe presented a hand-written letter from Kim to the Chinese President, although no details of its contents were given at the time, the source close to Pyongyang and Beijing has now described it as "terse".

China has grown increasingly frustrated with Pyongyang and a former senior U.S. official said Beijing's insistence that North Korea halt testing would be in line with recent signs it was running out of patience.

"What I've heard from talking to Chinese officials and American officials who are talking to them is that top Chinese officials now emphasize that the principal goal is to terminate the nuclear weapons programme of North Korea," the ex-official said.